20 
Immediately after the completion of the chalk there is 
evidence to show a general movement upwards, since what had 
been deep sea was converted to shallow water and subject to 
inundations from land ; all tending to prove not only a 
decrease of temperature, but also an expansion of the crust. 
The internal density of the earth was also relieved at this 
period. In Ireland a very large tract of basaltic rocks occu- 
pies the country of Lough Neagh, and near Coleraine the 
thickness of these rocks is 1,000 feet, their superficial area 
800 miles. 
Therefore we may conclude that the thickness of the 
expanded earth's crust from the Permian to the bottom 
of the Tertiary, computed by Sir H. de la Beche, is 1,750 
yards = one mile ; from the Permian to the Old Red Sand- 
stone, two miles ; Palaeozoic, as before, six miles ; total 
thickness of elevated rocks to the Tertiary, nine or ten miles. 
The tertiary series. The eocene, miocene, and pleistocene 
periods. Between the chalk and these tertiary beds is a 
remarkable discordance as to organic remains, none being 
common to both. Lyell says this abrupt transition from one 
set of fossils to another is also accompanied by evident signs 
of a change of climate, the eocene tertiary fossils having a far 
less tropical aspect than those of the chalk. 
There are also signs of a great increase of land in Euro- 
pean latitudes, by reference to the map of Lyell, which 
shows the immense area converted from sea into dry land, 
and in some cases from deep sea into mountains of 
great altitude, especially of chalk. The secondary beds 
below the chalk are exclusively marine, while the 
tertiary contain lacustrine, fresh water, and marine beds, 
alternating. 
The map (Boues) demonstrates that about two-thirds of 
the present European lands have emerged since the earliest 
tertiary beds originated, the change of climate and increase 
